Brushbars are used in vacuum cleaners in order to agitate dirt on a surface being cleaned. Agitation helps lift dirt from a surface so that it can then be sucked up into a separator.
An example of a brushbar is provided in GB2526512A. The brushbar comprises a cylindrical body and two strips of bristles, which may comprises a strip of NYLON bristles and a strip of carbon fibre bristles. The strips of bristles extend in respective helixes about the cylindrical body. Typically, each strip of bristles comprises a strip of material to which the bristles are attached. Carbon fibre bristles may, for example, be secured to a strip of relatively stiff polymeric material by stitching. NYLON bristles are typically bonded to a flexible strip of fabric which itself may be NYLON. Channels having retaining lips on each of their respective sides are typically formed along a body of the brushbar. The bristle strips extend along the respective channels and are held in place by the retaining lips.
In order to assemble such a brushbar, each bristle strip must be threaded from one end along a channel. If the depth of the channel is too shallow, the force required to force a strip along the channel risks deforming the bristle strips and, in the case of NYLON strips which are typically more flexible than the carbon fibre strips described in the example above, can make it very difficult and potentially impossible to completely insert the strip into a channel Conversely, if the depth of the channel is too deep, the spacing between the underside of each strip and bottom of each channel is such that the strip moves in the radial direction during use of the brushbar. This makes floor clearance difficult to maintain and, in the case of the NYLON bristles which tend to be stiff, can result in a bristle strip being pushed up into the channel thereby reducing the amount by which the bristles penetrate a carpeted surface, and adversely affecting pick-up performance.
A brushbar which does not have the drawbacks mentioned above is therefore desirable.